This invention relates generally to the ink-jet printing art for ejecting ink droplets on a recording medium, such as paper, and more particularly, to a method of filling ink into an ink tank cartridge for use in an ink-jet type recording apparatus, such as a printer.
In a conventional recording apparatus, ink is supplied to a recording head from an ink tank constructed as a cartridge. A benefit of using an ink cartridge serving as an ink tank is that ink does not smear due to the leakage of ink while refilling new ink or the like. However, undesired air bubbles can easily enter the ink tank during the filling process which cause problems such as ink supply failure.
A cartridge is often divided into multiple chambers, where ink is stored in a porous foam or material positioned over an outlet port in one chamber and free ink is stored in the other chamber. The free ink migrates from its chamber into the foam through an opening providing communication between the two chambers. The foam then controls the flow of ink as it migrates toward the ink outlet port.
It is known to fill an ink cartridge by introducing ink via a vacuum into the porous foam. This filling method is used in an effort to limit the introduction or retention of air bubbles in the ink cartridge. Air trapped in the cartridge adversely impacts the ink supply to the printhead or can mix in the ink resulting in poor printing quality. In addition, entrapped air in the ink cartridge can result in decreased storage or shelf life of the cartridge. Accordingly, alternative methods of filling have been explored but have failed to adequately address the air entrainment issue.
It is desirable to develop a new and improved method of filling ink into an ink tank cartridge to substantially eliminate air within the ink and provide better, more advantageous overall results.